404 HORSE, SWINE AND POULTRY DISEASES 



a nerve has been inflicted, but whenever this is possible it may 

 enable us to remedy that which otherwise would result in permanent 

 evil. Treatment should consist in relieving compression, in hot 

 fomentations, the application of liniments, excision of the injured 

 part, and rest. 



TETANUS, OR LOCKJAW. 



This disease is characterized by spasms affecting the muscles 

 of the face, neck, body, and limbs, and of all the muscles supplied 

 by the cerebro-spinal nerves. The spasms or muscular contractions 

 are rigid and persistent, yet mixed with occasional more intense con- 

 tractions of convulsive violence. 



Causes. This disease is caused by a bacillus that is often found 

 in the soil, in manure and in dust. The germ grows only in the ab- 

 sence of oxygen. It produces a powerful nerve poison, which causes 

 the symptoms of tetanus. The germ itself multiplies at the point 

 where it is introduced, but its poison is absorbed, and is carried by 

 the blood to all parts of the body, and thus the nervous system is 

 poisoned. Deep wounds infected by this germ are more dangerous 

 than superficial wounds, because in them the germ is more remote 

 from the oxygen of the air. Hence, nail pricks, etc., are especially 

 dangerous. In the majority of instances the cause of tetanus can be 

 traced to wounds, especially pricks and wounds of the feet or of 

 tendinous structures. It sometimes follows castration, docking, the 

 introduction of setons, inclusion of a nerve in a ligature, etc. It 

 may come on a long time after the wound is healed three or four 

 months. In some countries where tetanus appears to be enzootic 

 the presumption is that it is due to a specific germ. Horses with a 

 nervous, excitable disposition are more predisposed than those of a 

 more sluggish nature. Stallions are more subject to develop tetanus 

 as the result of wounds than geldings, and geldings more than 

 mares. 



Symptoms. The attacks may be acute or subacute. In an 

 acute attack the animal usually dies within four days. The first 

 symptoms which attract the attention of the owner is difficulty in 

 chewing and swallowing, an extension of the head and protrusion 

 over the inner part of the eye of the membrana nictitans, or 

 haw. An examination of the mouth will reveal an inability to open 

 the jaws to their full extent, and the endeavor to do so will produce 

 great nervous excitability and increased spasm of the muscles of 

 the jaw and neck. The muscles of the neck and along the spine 

 become rigid and the legs are moved in a stiff manner. The slight- 

 est noise or disturbance throws the animal into increased spasm of 

 all the affected muscles. The tail is usually elevated and held im- 

 movable; the bowels become constipated early in the attack. The 

 temperature and pulse are not much changed. These symptoms in 

 the acute type become rapidly aggravated until all the muscles are 

 rigid in a state of tonic spasm with a continuous tremor running 

 through them; a cold perspiration breaks out on the body; the 

 breathing becomes painful from the spasm of the muscles used in 

 respiration; the jaws are completely set, eyeballs retracted, lipa 



